Effects of soil erosion on natural radioactivity in water in a typical quarry lake in Vietnam based on model assessment

A quarry lake is a quarry that is filled with water after abandonment. In the lake water, natural radionuclides contaminate with a certain level, as a result of atmospheric deposition, groundwater diffusion, soil erosion, and sediment–water–air interaction. In this study, 40 K, 226 Ra, and 232 Th were analysed for surface soil and water in a specific quarry lake in Vietnam. The seasonable variation of radioactivity in water was investigated. It was found that the activity concentration correlated with the TDS of water and the higher activity concentration was found in the wet season. The RUSLE model was used to predict the average annual rate of soil erosion in the study site. Based on the model prediction, the inflow rate of 40 K, 226 Ra, and 232 Th in water were 4.73, 36.75, and 768.5 GBq y −1 respectively.